Conventionally, it has been proposed to use silicon carbide (SiC) as a material for a semiconductor device. A substrate made of such silicon carbide is manufactured, for example, by an improved Rayleigh method.
However, a silicon carbide substrate manufactured as described above has a problem that openings are formed in a surface thereof and micropipes, which are crystal defects extending in a c-axis direction, are often generated. When an epitaxial film of silicon carbide is formed on the surface of the substrate, crystal defects also occur in the epitaxial film due to the presence of micropipes in the surface of the substrate, which may cause a deterioration in electrical characteristics of a semiconductor device eventually obtained.
To solve such a problem, for example, Patent Literature 1 (Japanese Patent Laying-Open No. 2004-292305) discloses a technique for liquid phase epitaxial growth implemented by overlapping a seed crystal substrate made of a silicon carbide single-crystal and a polycrystalline silicon carbide substrate with a silicon source interposed therebetween, housing them in a closed container, thereafter heating the seed crystal substrate and the polycrystalline silicon carbide substrate to 1400° C. to 2300° C., and, with a ultra thin silicon melt generated from the melted silicon source interposed between these substrates, growing a silicon carbide single-crystal on the seed crystal substrate by a liquid phase epitaxial growth method. Patent Literature 1 describes that the silicon carbide single-crystal epitaxially grown by the method as described above can have a reduced micropipe density.